Telephone-exchange system.



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TELEPHONE-EXCHANGE SYSTEM.

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Original appicaton filed April i, 19U5, Seriaito. 253,227.

Specification of Letters Patent.

1910. Serial N0. 597,353.

To all whom t may concern.'

Be it known that i, CHARLES LANE Gool)- RUM, a citizen ot the United States, residing at Urbana, in the county of Champaign and State of Ohio, have invented certain new and useful improvements in Telephone-EX change'Syst-ems, of which the following is a specification. Y

My invention relates to telephone exchange systems and has forits object the improvements of said system'particularly in the means employed for ringing or signaling a called subscriber; this applicationbeing a division ot my pending application No. 253,227, iled April 1st, 1905.

In the accompanying drawing l have shown the invention as applied to an ex-A change in which automatic means for effecting a connection between a calling and called subscriberis employed; the particular means ot setting up a connection from one subscriber to another, however, is 'not involved in this application, which as stated relates to signaling means and particularly to such as is'generally known as automatic ringing.

The accompanying drawing which forms a part of the specification is a diagram showing my invention as applied to what is generally known as a three Wire automatic common battery or central energy system.

lin the drawing A. and A represent two subscribers stations each equipped with the usual telephone outlit, and calling devices adapted to work in a common battery'a-utoma ic system the calling devices being preferably such as have generally been known as the Strowger device which are adapted to send impulses .from ground, first over one side of the line and then over the other to effect the operation of the switches.,

Lines 1 2, 3 4 from these stations terminate at the exchange in suitable contacts to which connection may bc made by meansc of switches, said lines also having connections to suitable switching mechanism by" which connection may be made, from one of'l said lines to the terminal contacts of other?A lines tor conversation. For the purpose of illustration l have omitted the intermediate switches for establishing the connec- ,tion between lines showing only what is known as the connector switch in connection with which have shownmy improved mechanism for automatic ringing. wt will be understood that any of the well known means for setting up connections between subscribers by means of various switches may be employed the means illustrated be ing adapted to be operated by the well known method of sending impulses from ground over the opposite sides of the subscribers line to operate the switches in establishing a desired connectionA and Jrior grounding both sides of the iine'for releasing and returning the switches to their nor mal positions. i 4

n said drawings a represents the rotary shaft otl a primary or selector switch having wipers o2 and a8 which through the operation of the switches not shown) have been brought into contact with the line terminals m1 ot. the connector switch, thus connecting the subscribers line into 'the connector switch in the usual way. This shaft also has ari-operating circuit wiper a4 which has been brought into contact with the terminal m9 of the connector switch. This last mentioned wiper c4 has been, in the operation of the switch mechanism, grounded, so that when it rests on the terminal 'm9 a cir cuit is closed to the relay M19 over the following circuit: grounded wiper at, contact fm, wire 95, connector switch wiper g3, Wire 96, switch relay M19, wire 97, main battery B to ground. The relay M19 willth'iis be energized and in pulling up its armature `operates a number of contacts one pair of which opens one side of the line 98-99 and another pair opens the other side 10G-101, these lines being shown in heavy black and constituting the main lines or talking cir cuit when the connection is completed, said -lines being thus held open during the subsequent operation of the switch or so long as the relay M19 is energized.

Operating relaysMf21 and M2? are normally connected to the opposite-sides of the ot relay Mzl'bcing traced-iisV Yhallows: line 98, relay M21, wire 102, Contact 163, spring 10a, .Wire lO, battery B and ground. The

relay M2? being connected to line wire 10Q?,v

as follows: wire 10G,"relayA v4wim 106;,

contact 107, spring 108, wire .109, contact 110, springvlll, wire 112, wire 105, to battery B and ground. Contacts 103,-104 and 107108 are vcontrolled by relay M25, whilev contacts 110-111 are controlled by relay `M2' as' hereinafter described. Relay M21 controls the spring 93, which engages contact 94 in the local circuit of the motor ma netll/ 24 as follows: from-battery B, Wire 9%, wire 92, spring 91, contact 90, wire 89, motor magnet M24, wire 88, spring 93, contact 94, wire 87, spring 86, contact 85, wire energized which would occur when No. l I

line is grounded' at the calling subscribers station. The motor magnet M2A1 is adapted to operate the rotary shaft g of the connector switch step by step in response to impulses received by the operating relay M21 inthe usual way and carriesthe wipers g1, g21-g2, g2.-g2. The wiper g1A is connected' to the ringing relay ll/ 2 in the manner he.; einafter described. The wipers g21 and g2' are the main line wipers and adapted when the switch is properly stepped around to rest upon the terminals of the called line. 'Said Wipers being connected to the opposite sides 99 and 101 of the main lineV through contacts controlled by the relay h 2", wiper a2 being the test or busy wiper. As the shaft,

g is rotated in stepping around the switch, the relay M1 which was previously energized by wiper g2@ resting on a grounded contact would be held up over a local circuit including the contacts 115, 116, controlled by its own armature, the circuit be# ing traced as follows: battery, wire 97, relay M12, wires 113-114, contacts 115-116, wire 117, contacts 118-419, wire 120, to grounded battery. The contacts 118-119 are controlled by the relay M22so that relay M19 will be energizedpso long as relay M22 remains in its normal position and the shaft g may be stepped around as necessary or until the wipers g21, g2 rest upon the contacts of the called subscribers line. As soon as the shaft has been stepped around in. respense to the impulse over No. 1 side ofthe line with wipers ,72h-g2 resting on the terminals of the called subscribers line a single impulse will be sent over the No. 2 side of the line following the usual so called Strowger method of sending impulses. This will energize the relay M22 and open the circuit of the relay M12 at contacts 118-119 and allow the said relay to assume its normal position, thus closing the lines 98-99,100-101 which constitute the talking circuit and also opening" the' motori magnet circuit. The

p talking circuit lthus being connected through from the calling subscriber A to the called subscriber A1 whose terminals are engaged by the ,switch wipers g214-g2- It will be noticed that wire 117 which forms a part of the holdingA 4circuit for relay M19 isV branched from wire 121 tothe wiper g3 and the contact m11 which is engaged by this wiper g3. In case la called subscriber is busy, wiper g1 isgrounded,'so that in the event that the vline called was busy vM19 would not berdenergized by the operation of the relay B 22, but it would beheld energized overthe circuitbefore described; to

wire 117 and thence bywire 121, wiper g2K and .grounded contact' m11. So. long' as relay M1 is kept energized the main or trunk at the contacts controlled by 'this' relay so that the calling subscriber could not be connected to a busy'line.

Assuming, however, the line is not busy,

the relay M19 will be denergiaed by the pulling up of relay M22 undertheiniuence of the single impulse coming over the No.

tact' m11 would operate the cutoff relay (not shown) of the called subscriber in .the usual way, torender the called subscriber clear from any connection with any individual or selector switch. V

The calling subscriber now being connect ed to the called subscriber it remains necessary to supply generator current to the called line for the purpose of ringing or signalingr the called subscriber.- his is accomplished automatically by the Wiper g1 resting upon the contact m12 connected through interrupter m to ground. The wiper g1, as before Stated, is connected to the relay M21 over the following circuit; the wiper g1, vwire 75, relay M2, wire 74, contact spring' 72, wire 71, contact 70,`spring 91, wire 92, wire 97, battery and ground. -The contact m12 being periodically grounded through the interruptor m periodicallyenergizs there-l lay M2 which upon attracting its armature separates the contacts in the lines 299-5109v which lead to the wipers g21-g2 and also closes the ringing circuit to one of the said wipers4 and which are now in connection as before stated, with the called subscribers station. As the relay M26 is intermittently energized and denergized by the grounded A nterrugi er, ringing, current will be emptied odlcally to the called subscriber until sprin' G2 one side oit the talkingr circuit Y e, s 9 n 'ier y", lin-e wire Li, subscribers ringer,

er eno ground culd be stated that the main or trunk ruling the talking circuit are sepa- 'o rated in. the usual. Way at the connector switch condensei's'as shown located in lines 9&100 thus conductively separating nd ci the line from the callingr line, and battery supply relays e provided one of which is conni. one side of the line to battery und ,tire and the other to the other side of 'the )ne and ground thus bridging said relays on the called side of the line with interposed battery so that said relays will be simultaneously energized when the called end et the line is closed by the removal of the telephone from the hook., The circuit for the relay M25 is as follows: Yfrom line 9S; Wire 5G, relay M25, Wire 51, Wire 120, wire S- tc ground. The circuit for relay M2T is from line Wire 100, wire 52, relay 4i 27, Wire `wire 5, battery Id and `aground. When the cailedsubscriber answers and closes his line by removing his telephone receiver these relays iw and M27 being bridged across the the line with interposed batte. 1, he simultaneously energized and the current thus tiowing over these lines will j t l ig battery to the called end of i -ne energization ot relay M25 opens the circuits of relays M21 and M22 at hack contacts 103, 104;, 107, IGS through which the circuits for said relays (as before described) pass. The encrgization of relay ,li/ll closes its forward contacts which closes the circuits of relays M18 and M20 which are thus bridged across the calling end of the linel with interposed battery and thus furnishestallring current to the calling end oi line olver the following circuit: battery wire 41.0, relay Mzfwire el., contact 42, ing?,f 43,; wire 44, to main line Q, thence nested z ba lr through the switch Wiper as to the callwiper c2, main line 9S, wire v42,5, spring 46, contact 4'1", Wire 48, relay M18, Wires 49, 5l, 120, to grounded. side of battery. The energization of relay M20 also opens the circuit tor relay M26 at back contact 72, 73, through which the circuit for said relay heretofore described, thus dener- 'd relay cutting otl the ringing Il l line and connectingthrough the der' :ci the operation it should be remembered that there is employed at the 'in subscribe-s stations the usual Strowger appa- T59 ing, subseribers station through the switch closing the calling subscribesV ratus the essential parts of which comprise the dial, receiver hook with contacts contrclled by each arranged and operated as in standard apparatus of this type, that is the receiver hook is adapted when released (by removing the receiver)g 'to bridge the transmitter and receiver across the line through the induction coil and when the hook is depressed (by hanging up the receiver) it opens the said branch and in its downward movement closes both sides of the -line to ground to effect the release of the switches'. IrEhe contacts operated by the dial are so arrange-d that upon the irst movement of the dial it opor slthe bridge of the subscribers instruin ts, in its backward move ment it grounds iheNo. l side of the line a number of times corresponding to the inipulses to be transmitted, upon returning to normal it monunitarilyy grounds the No. 2 side of the line to despatch 1a single impulso oi current thereovcr and finally in arriving at its normal'position closes the bridge for the talking instrument. The sub-station cir the called subscriber has been automatically signaled and has answered by removing his receiver and has thus supplied talking current to his own end of the line through the relays M and M2? which in operating have bridged the relays M18 and M20 across the callingl end of the line with interposed battery thus supplying talking current to the calling end of the line. l

For releasing the switches release relays are supplied in each of the switches which are adapted to be operated upon the operatlon of the release relay of the succeeding switch so that the switches will bc released in the reverse order to that in which they are set up in the usual Way. it will be only necessary to describe the means for operating the release relay M23 of the connector switch, which 'may be accomplished in seyex'al different Ways. y It at the end of the conversation the Called subscriber hangs up iii-st both sides .of

yis on the Wet side of the battery Will be held u `This will energize the release magnet 1V 23 over the following circultzvground in line,vthe relay mi? being on the grounded' side of the' line will be' denergi'zed and' close its vcontacts while the relay M20 will l remain energized thus closing its contacts the circuit as before up to wire l2, vthence -by wire 20, contacts 2l, 22, Wire23, contacts 2l," 25, wires 2G, 105, battery. and ground. A y

`inthe event that the called subscriber did 'not answer or was busy then the relays M21 Vand M3? Would he connected to the opposite sides of the lines and the calling subscriber hanging ,up Vwould ground both sides ofthe line cnergiaing relays 'M21 and M2Z thus 'Y closing the release circuit by wire 27, spring 28, dontact 29, Wire 30, c'ontact 3l, spring 32, wire 2li, 105, battery and ground thus releasing the switches as before.

Having thus described my invention, l vclaimt' 7 l. Ina telephone exchange system, the

combination with a'. central exchange, of.

sub-stations connected therewith through telephone lines, a connecting circuit at the central exchange, a source of ringing cur- 'rent at the central. exchange normally disconnected from the connecting circuit, a re lay controlling the connection of said source with the connecting circuit,a second relay controlling the circuit'foi; said first relay, an interrupter means in 'said circuit for periodically causing closure of said circuit `to periodically cause action of the tirst relay to connect the source with 'the connecting circuit and with a line connected therewith, substantially asdescribed.

calling and-a called subscrihers line, a link 'circuit having switch terminals 'for interconnecting them and an automatic connector switch operating in connection vwith said terminals, a ringing relay actuated when the connector switch has selected the terminals of a called 'line-to connect a rino*n Ying ener'atorvwith said called. lineV only, toget er with an intermittent circuit closer actuate the same at intervals, and means controlled by .the called subscriber for dis abling said relay when the call is answered, substantially as described'.

3.111 an automatic telephone system, the combination with a plurality of normally and release relay M23 will he energized overl 2. In a telephone exchange system, -a-

adapted to close the circuit of said relay and maaier open instrument' circuits each provided with signaling dev1ces,'a connector switch com prising terminals for said lines and having Wipers `cooperating therewith which serve to connect one, a calling circuit, with another a called circuit, and mechanism. foroperating the' wipers, ot a source of current for sigg-v naling purposescomprising a circuit 'which is normally disconnected. from the hist-rument circuit, a signaling' relay which is intermittently operated and controls contacts lwhich open the callingv end of the line and connect 'the signaling circuit to the called end .thereof automatically upon the cessation of movement of the switch wipers.

4. ln an automatic telephone system, the combination with a plurality, of normally .open instrument circuits eachv provided with signaling devices, a connector switch com-V prising terminals for said lines and having Wipers cooperating therewith which serve to connect one, a calling circuit, 'with another a called circuit and mechanism `for operating the Wipers, or' a sourcefo'r1 current for. vsignaling purposes comprising a circuit which is normally disconnected from the in strument circuit, a signaling relay .which is intermittently operated and controls contacts which open the calling end oit the line and connect` the signaling circuits toA the .called end thereof automatically upon the cessation of movement of the switch i-:f'ipers and another relay adapted to be operated when the called instrumentv circuit is closed and `While the signaling circuit is disconnected4 therefrom. to render 'the signaling relay inoperative;

5. ln' a telephone system a telephone line to be called, a connecting circuit for estalilishing connection with said line,v abridge across the conversation strands of said conmeeting. circuit, a 'relay and a battery -n said 1bridge, a' ringing generator, a ringing relay adapted when 'actuated to 'sever the conversa tion strands of said connecting circuitv and connect said ringing generator .with the call ing end thereof, a continuously operating interrupter brought into circuit with said ring ing relay 1n response'tc the connection ci' said connecting circuit with said line, said bridged relay having, contacts controlling the circuit oi said ringingrelay and interrupter, said bridged relay being energized over the called telephone line when said line is closed at. its substation and when said ringing relay is in ,itsnor'mal condition to cause interruption of the circuit oit the ring ing relay 'and thus prevent theffurther ac tuation of'l said interrupter from connecting said generator with the called line.

6.' In a telephone system a telephone line',

a link circuit having1 terminals for connec# tion With said line, a ringing generatar`,aA ringingrelay for connecting' said generator with saidline, a continually operating cir,n

i cuit interruptenua disabling relay having normally closed contacts in the circuit of said ringing relay and said circuit interrupter, a battery, and a relay connected between said battery'and said line during the nonactuation of said ringing relay and operated upon the response of the called subscriber to close the circuit of said disabling relay and thus interrupt the circuit of said ringing relayn 7. In a telephone system a telephone line, a link circuit having terminals for connection with said line, a ringing generator, a ringing relay for connecting said generator with said line, a continually operating circuit interrupter, a disabling'relay having normally closed contacts in the circuit of said ringing relay and said circuit inte/rrupter, a battery, a relay connected between; said battery and said line during the non. actuation of said ringing relay/and operated upon the response of the called subscriber to close the circuit of said disabling relay and thus interrupt the circuit of said ringing relay, and means to prevent the reclosure of the interrupter circuit when the called subscriber reopens his line at the termination of his conversation.

8. In a telephone system a telephoneline, a link circuit having terminals for connection `with said line, a ringing generator, a ringing relay for connecting said generator withsaid line, a continually operating circuit interrupter, a disabling relay having normally closed contacts in the circuit of said ringing relay and said circuit interrupter, a battery, a relay connected between said battery and said line during the nonactuation of said ringing rclayvand operated upon the response of the called subscriber to close the circuit of said disabling relay and thus interrupt the circuit of said ringing relay, and means to prevent reringing the` called subscriber at the termination of the f co'nversation.

4 In testimony whereof, I have hereunto set my hand this 12th day of November, 19m.

CHARLES LANE GOODRUM.

Witnesses:

CEAS. I. WELCH, ELSA K. SMITH. 

